Overexpression of rice NAC gene SNAC1 in ramie improves drought and salt tolerance

Transgenic technology is probably the best way to improve crops when traditional breeding is not feasible. Ramie is one such plant because the heterozygote complicates breeding efforts. This study is the first to report the successful production of transgenic ramie plants which is tolerant to drought and salt stress. In this study, the stress responsive gene SNAC1 (STRESS-RESPONSIVE NAC 1) was first introduced into ramie by Agrobacterium-mediated transformation which was using leaf midribs as explants. The overexpression of SNAC1 significantly enhanced drought and salt tolerance at the seedling and fiber maturation stages, via observation of phenotype and yield between transgenic plants and wild-type ones. SNAC1-overexpressing ramie plants also showed significantly improved tolerance to both drought and salt stresses at the rapid-growth stage. The transgenic plants had higher photosynthesis rates and relative water contents compared to the wild-type plants during the rapid-growth stage under drought and salt stress. Our study indicates that ramie's tolerance to drought and salt stress can be improved through genetic engineering.